Poole Harbour Guide 2011 - Poole Harbour Commissioners

107
Tidal Streams
Harbour Entrance
The stream between South Haven Point
and Sandbanks begin as follows:
Interval from LW
Poole Harbour
Direction
+00:55 In-Going
– 06:45 Out-Going
The maximum spring rates are 3kn for the
in-going stream and 4 3 /4 kn for the outgoing
stream, which is weak for the first
three hours. At neaps the streams are
weak and uncertain.
Strong tide rips occur on the NE side of
the entrance both on the in-going and outgoing
streams.
The following description refers to the
tidal streams in Poole Harbour,
between Brownsea Roads and the
Port of Poole, at springs. At neaps the
streams are weak and uncertain.
In Brownsea Roads, the in-going stream,
spring rate 3 to 3 1 /2 kn begins +00:55
Poole Harbour; the out-going begins
–06:15 Poole Harbour but is weak until
–02:30 Poole Harbour after which it runs
strongly and attains a rate of 3 knots at
springs.
From Brownsea Roads the in-going
stream runs at first in the buoyed
channels; later as the mudflats cover, it
runs across them towards Poole. In the
channels the in-going stream begins
+00:40 Poole Harbour and attains a rate
of 2 1 /2 to 3kn at springs, but its rate
decreases when the mudflats cover. The
out-going stream begins about –06:30
Poole Harbour but is weak until –02:30
Poole Harbour after which it increases and
attains a rate of 2 1 /2 to 3kn at springs.
In The North Channel the in-going
stream begins +00:55 Poole Harbour and
attains a rate of 2 1 /2 kn at springs. The outgoing
stream begins about -06:30 Poole
Harbour but is weak until about –02:15
Poole Harbour after which it increases and
attains a rate of 3kn at springs.
In Little Channel and off Poole Quay the
in-going stream begins +00:55 Poole
Harbour and runs at first in the direction
of Little Channel; off The Quay it splits
and, while the main stream continues
west, a weak stream also runs east along
the eastern part of The Quay. As the
mudflats cover the in-going stream runs
across them, diagonally across Little
Channel and west along the whole length
of The Quay. The in-going stream attains
its greatest rate. 2 to 3 kn at springs,
quickly but about 2 hours later, as the
mudflats cover, it decreases to 1 1 /2 to 2 kn
at springs.
The out-going stream begins –06:45
Poole Harbour and at first runs, from the
bridge, east along the quay and SE across
Little Channel; later, as the mudflats dry, it
runs more and more in Little Channel and
the stream along the east part of The
Quay decreases. At first the out-going
stream is weak and after about -02:30
Poole Harbour it increases and attains a
rate of 3kn at springs in the river and 2 1 /2
to 3kn along the east part of The Quay
and across Little Channel. As the mudflats
dry the stream in Little Channel attains a
rate of 3kn.
Tidal observations taken in 1977 in
Brownsea Roads and in Little Channel give
mean spring rates 1/4 to 1kn less than
those quoted above; the quoted rates are
approximately maximum spring rates.